CORE 1 - ANIMAL PHYSIOLOGY CORE: ABSTRACT The purpose of the Joslin Animal Physiology Core is to provide technically advanced physiological evaluation of rodents for the study of diabetes, obesity, and their associated complications. The study of animal models is an integral part of Joslin Research, and DRC investigators maintain more than 14,000 mice and rats in the Joslin Animal Facility, and more than 8,000 mice offsite. Joslin DRC investigators have generated approximately 170 strains of genetically engineered mice during the last 20 years, the majority of which have been studied using the Animal Physiology Core. Core services provided by the Animal Physiology Core include: Comprehensive Laboratory Monitoring Systems (CLAMS) for the measurement of in vivo energy expenditure, activity and fuel utilization; Dual Energy X-ray Absorptiometry (DEXA) for assessment of body composition; measurements of ECG, EEG, arterial blood pressure, blood glucose levels, and core body temperature in mice and rats using telemetry systems; hypoxia and hyperoxia using an OxyCycler; IVIS Spectrum CT for in vivo animal imaging; diurnal incubators for controlled exposure to cold and thermoneutral temperatures; exercise using a rodent treadmill and activity wheel cages; muscle strength of rodents in vivo using a grip strength meter. As part of the Animal Physiology Core, Joslin will establish during the coming year a dedicated Germ-Free Mouse Facility to study the role of the microbiome in metabolic diseases. Another critical role of the Animal Physiology Core will be to continue to educate investigators and fellows on the theoretical understanding of core procedures and data collection, to consult on study design, and to provide hands-on training for some procedures and equipment. The Animal Physiology Core has consistently provided services to DRC investigators (approximately 15/year) and has been essential in the publication of multiple papers in high impact journals such as Nature, Cell Metabolism, and the Journal of Clinical Investigation. Joslin support for the Animal Physiology Core has been substantial with the purchase of many new pieces of equipment and maintenance of current equipment. During the next year Joslin will fund physical development of the transitional Germ-Free Mouse Facility at a cost of approximately $200,000. All of this support will continue to keep Joslin's animal-based research at the forefront of diabetes research.